LASER pdf hsujsnshsusnsnssmsjjsujsjsjsj.pptx

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1. 1 Indian Institute of Technology Indore LASER Components of Laser Active medium/ Laser medium / Gain medium Pumping Source/ Energy Source Optical resonator/ Resonator cavity

2. ACTIVE MEDIUM 1. An active medium is the material in which the lasing action takes place. The medium may be solid, liquid or gas. 2. Out of different atoms in the medium, only a small fraction of atoms of a particular species are responsible for stimulated emission i.e. for lasing action. 3. Those atoms that cause laser action are called active centers and the rest of the medium acts as host and only support the lasing activity.

3. PUMPING SOURCE To achieve and maintain the state of population inversion, the atoms must lift continuously to the exciting level. The pumping agent is an external source that supplies the energy needed to obtain the condition of population inversion. Different types of pumping agents are available and used according to the requirement of the medium. 4. Optical pumping, electrical discharge, and direct conversion are some of examples of pumping agents.

4. OPTICAL RESONATOR (RESONATOR CAVITY I] An optical resonator consists of two opposing plane parallel mirrors, with an active material placed in between them. Out of the mirror is partially reflecting (semi-transparent) whole other one is made of a 100% reflecting mirror. This structure is known as a Fabry-Perot resonator. II] A resonator cavity is a system that amplifies the stimulated radiation and intensity of the beam.

5. OPTICAL AMPLIFIER An optical amplifier is a device that amplifies the optical signal directly without ever changing it to electricity. The light itself is amplified. Reasons to use the optical amplifiers Reliability Flexibility Wavelength Division Multiplexing (WDM) Low Cost Variety of optical amplifier types exists, including Semiconductor Optical Amplifiers (SOAs) Erbium Doped Fibre Amplifiers (EDFAs) (most common)

6. EDFA (Erbium doped fiber amplifier) In general, EDFA works on the principle of stimulating the emission of photons. With EDFA, an erbium-doped optical fiber at the core is pumped with light from laser diodes. This type of setup in telecom systems can help with fiber communications, for example, boosting the power of a data transmitter.